1. Field of the Invention
The present invention relates to a working vehicle in which a transmission case is supported on a vehicle body frame, the transmission case speed-changing a driving force from an engine and transmitting the driving force to left and right rear wheels. More specifically, the present invention relates to a configuration in which the transmission case is detachably supported on the vehicle body frame.
2. Description of Related Art
As a working vehicle configured as described above, Related Art 1 discloses a configuration in which an engine support frame is arranged at a rear portion of a vehicle body; a suspension frame is detachably provided on an L-shaped pipe, the L-shaped pipe constituting the engine support frame; and rear wheel differentials and the like of rear wheels are supported on the suspension frame.
In the configuration of Related Art 1, the suspension frame is detachably provided. Therefore, a drive system of the rear wheels is detached together with the suspension frame.    [Related Art 1] Japanese Patent Laid-Open Publication No. SHO 63-20284
The suspension frame disclosed in Related Art 1 achieves suspension functionality by vertical displacement integral with the rear wheel differentials and the like that drive the rear wheels. This configuration is effective for a vehicle having a lightweight drive system such as a relatively small buggy.
However, for a working vehicle having a large and heavy transmission case, in a configuration in which a drive system of the rear wheels, including the transmission case, is supported on a suspension frame, not only does a movable part become large and heavy, it also leads to large suspension unit systems such as suspension springs. Therefore, there is room for improvement.
A configuration in which a drive system can be separated from a vehicle body frame integrally with rear wheels not only facilitates maintenance and repairs, but also is desired in terms of assembly, because, when assembling a working vehicle in a mass production line, the drive system of the rear wheels can be pre-assembled and unitized.